1. Field of the Invention
The present invention relates generally to converted wood articles and composite wood products made therefrom for use in general construction primarily but not limited to posts, flooring, walls, and support beams.
2. Description of the Related Art
The depletion of old growth forest has placed increasing demand within the forest industry for alternative wood products which make better use of old growth and stagnant growth timber and which also provide for greater use of second, third and later generation trees, as well as plantation tree thinnings and pulpwood. As the supply of large old-growth timber continues to be depleted, larger and larger amounts of smaller-sized timber, such as second, third, and subsequent growth timber and plantation timber will be converted into usable wood products. Since in the past it had been common practice with the large old-growth logs to have the freedom and flexibility to manufacture large-dimension wood products of various types, it is now necessary to conceive new products and methods of manufacture to convert the smaller-diameter timber into wood products that have the necessary dimensional and structural characteristics.
Several alternative wood products have emerged in an effort to address some of the needs in the industry. In this respect U.S. Pat. No. 4,394,409 discloses a composite wood product formed from four elongated triangular-shaped wood pieces. The four pieces are joined to form a composite wood product having a cross-sectional outline of a parallelogram and a hollow interior. An alternative embodiment is disclosed where each wood piece has a pair of machined keys to improve yield.
U.S. Pat. No. 5,299,400 discloses a composite wood product formed from four log parts, each log part having a three sided cross-section forming either right angled sectors and a third curved side or a right triangle. The log parts are assembled into a composite wood product so that their right angles form the corners of a rectangle with a hollow interior which is filled with concrete or other structural enhancing material. Similar examples of this alternative wood structure are disclosed in U.S. Pat. No. Re 35,327 and French Patent 962589. Other attempts to offer improved composite wood products are disclosed in French Patent 2512729 and German Patent 964637.
The present invention overcomes the deficiencies of the prior art.
The composite wood product of the present invention preferably includes a plurality of converted wood articles having a preferred cross-sectional profile. The cross-sectional profile is formed by at least an outer surface and at least two engaging surfaces. The engaging surfaces preferably include corresponding inter-engaging portions such that upon mating the engaging surfaces of adjacent converted wood articles, a joint is formed between the converted articles. The converted wood articles are then glued together to form the preferred composite wood product. The converted wood articles preferably include an extension surface extending between the outer surface and one of the engaging surfaces, whereby the joints between converted wood articles making up the composite wood product are displaced from the corners of the composite wood products. The composite wood product may include two pairs of opposing converted wood articles with each opposing pair of converted wood articles having a different modulus of elasticity. Further, the preferred composite wood product as described above may include standard wood pieces glued on opposite sides of the composite wood product to form a new composite wood product. The standard wood pieces on each side of the composite wood product may include wood pieces having a preferred modulus of elasticity.
The converted wood articles have cross-sectional shapes of four, five or six-sided polygons formed by notional lines through each of the surfaces forming the cross-sectional profile. Further, the sides of the polygons are arrayed such that a notional line through a joint between converted wood articles making up the composite wood product forms an acute angle with an outer surface of the composite wood product.
Still further, the present invention features a method of making converted wood articles including using converted wood articles having a specified grade or modulus of elasticity. Yet further, a method of making composite wood products may include disposing the converted wood articles in the composite wood product according to the specified grade or modulus of elasticity.